Apparatus for jet mining and excavating



Aug. l5, 1950 c. P. T. ASTON r-:/u. 2,518,591

Filed sept. 19, 1945 v APPARA'IUS FOR JET MINING AND EXCAVATING y '3 SheefsSheet 1 Aug. 15, 1950 c. P. T. AsToN E-rAL APPARATUS FOR JET MINING EXCAVATING 3 Sheets-Sheet 2- Filed Sept. v19, 1945 Aug.` l5, 1950 c. P. T. As'roN ETAL APPARATUS FOR JET MINING AND ExcAvATING Filed sept. 19, 1945 Patented Aug. 15, 4195() ABBARATUS GR JET'M1NINGAND y EXCAVATING'.

GecliP-ercyfloth: Aston, Bult-uruTand Charles4 Wil'd, Rayeld', NorthernfNi'gena': Appucationgsepmben 19, 1945; serial No. 617,192 InGreatBritain June 216A 194541-V This invention compr-i es-*improvements in or relating to mining andfexcavating alluvial deposits.

One offthe methods of obtaining minerals` com tained in underground' depositsisby'- sinking shafts anddriving fromrthese but-'this form of miningl has certain dis'aczl'vantages,l among which are il-oodingandv danger-f to human life: case: of alluvial deposits other Ways ofv obtaining the minerals are by open-cast working, dredging and the like, byA which' methods n itA is necessary` out by,alwaterejeticonsistsin sinking a pipe-into theground, directing. a-strongstream oil Waterl onJto .the= materiaiin lthe-vicinity vof the leadingv end of the pipe and therebyv washing out the material andrcarrying= itup`V through the p ipe Without necessitating removalof overburden.y

In'some-4 instances an existingshaft may be employedthrough which# the pipemaybe sunk to the vdesired'locationbutvvhere fresh-works are involved iti is Vconvenient to drivea boreihole fand sink a pipe therethrou-gl'rl which pipe4 substantially tsthe bore-hole One wayV of'makingthe bore-hole and sinking the pipe at the Sametime is toprovidenear'the'bottom ofthe pipe'a hydraulic jet directed'v downwardly' and" to cause the j et'to wash away the soil in frontofftlie pipe and'f elevate the material' of the. bore-hole through the pipe itself, the pipe being gradually lowered' as the washing. out operation proceeds y until the desired stratum isreachedfin which the material. exists which is yto be: mined or` excavated. Y

Several methods of carryingz the; present; invention. intoV eiect will ynow be; described withlreference tn the.v accompanying, drawings` whereof'z;

. Figure.; 1-n isv ai general viewiofrlan excavating; site.: dur-ing1i the formatifm.r oiI a borefhnie by.' a.'

In theY 2f sinking'runit in accordance'- witlrthe presentiinvention.

Figure 2 isa section tof-an. enlarged scale offlan:

underground working and of a sinking unit' during the formationin the overburden ofia-b'oreerv holeleading to a-mineralisedstratum which ist to .bef excavated.A

Figure 3 is a; section-ofi the-sinkingunit on Fig-ure 4 is aiperspectiveview of thevboring1 end:`

of the sinking unitshown inwFigures Iand .2.'y

Figure-5 is a section of the workings of'arr. ex-

cavating unitv provided' to remove themineralised;

stratum.

Figure 6 isa section'zon the line 62-6 of'Eigure 5.;

Figures 7 andffg areviews similar to Figurez showing modied excavating units in accordance with the: presentv invention.

Figures 8? and 1'()V are respectively sections one Figure 11 is afsectionallelevation ofapart off an excavating unitfshowing. a modification' thereof.

Referring toFigure 1, theV invention proposes to form a bore-hole' l5A in thev overburden I6 lsou that' the hole extends from the ground surface toa mineralisedstratum I1." which is to beV ex cavated without the removal of the overburden., The bore-hole' I5Lis. formed by a sinking uniti (generally indicated by the reference numeral iywhich isY suspendedv from a derrick l9`1so as to be held verticallyabove the bores-hole and so.

as to be capableI of movement into and out of thev bore-hole as desired. To this end the sinking.v unit is connected with a winch. Zilby. a rope 2|v whichapasses over a. pulley: 22 carried bythe der On the. surface of; theground concen1 tric with the sinking unitk |81 is laid'l a cast metalv apron 23 which is provided with a stuffing-gland? rick I9.

lllthrough which thevunit passes (see Figure 2'). The derrick l9 rests upon the apron 23 and'v presses it into the ground, the underside ofthe apron being Vprovided with three downwardly projecting annular flanges 2li-which are thereby: sunk-,into the surface of the ground andhelp to` keephe` apronin its true location.

The means described for enabling the sink-ing unit to be raised and loweredin the bore-hole issuchv as to permit the sinking unit to'be oscil;`Vv lated during the boring operation, the rotation being. effected by a belt 28 which passes around a pulley 2l and is driven from an e'ngine?8 Thesinking unit, as shown in Figures 2 and 3, comprises a main pipe 29 and an upcast pipe 39 whichi-.s-fof: abouthalf thediameter othe bere? of the main pipe and which serves as an outlet for excavated material. As shown in Figure 3, the upcast pipe is eccentrically disposed within the main pipe. The top of the main pipe 29 is closed and is formed with a branch pipe 3| by which water under pressure may be passed into the main pipe. The bottom of the main pipe is closed by a plate 32 (see Figure 4) through which the upcast pipe 30 projects, the upcast pipe being left open at the bottom' end of the sinking unit. In the plate 32 there is located a nozzle 33 through which the water which passes down the main pipe 29 is discharged to form a jet eccentrically disposed to the main pipe. The bottom edge of the main pipe is serrated around its periphery (as at 39) so that during rotation of the sinking unit the serrations will tend to cut into the ground and to loosen stones or like obstructions.

Water for the sinking unit is provided by a pipeline 34 (Figure 1) which passes to a pump unit 35, the delivery side of the pump being connected with pipe 3l of the sinking unit by a ilexible hose 36 which permits rotation and vertical movement of the unit. The upc'ast pipe 38 is connected by a flexible hose 3': with a pipe 38 which leads to a plant where the solid material in suspension in the out-flowing water is separated from the water by draining and is allowed to accumulate, or is disposed of to a dump or other- Wise treated as may be found convenient.

The Water supplied from the pipe 34 is passed to the sinking .unit at a high pressure by the pump and passing downwardly through the sinking unit along the main pipe 29 is discharged from the nozzle 33 as a high pressure water-jet which is directed parallel to the axis of the main pipe but eccentric thereto. Accordingly when the sinking unit is rotated as described, the Water-jet will wash out material below the sinking unit in a circle which is concentric with the pipe 29. If the jet is correctly located and fed with water under a suflicient pressure the re sult will be that material is washed out below the end of the sinking unit over an area which is slightly greater than that of the external diameter of the pipe 29 and all the material so washed away together with such material as is loosened by the serrations 39 is carried up the upcast pipe 30 and delivered to the pipe 38. As the ground is washed away from below the sinking unit, the latter is lowered into the bore-hole so formed.

In hard ground or rock, instead of forming the bore-hole by washing as described above, the hole may be partly or completely produced by the usual boring means, the object being to form a bore-hole which contains or will receive an excavating unit extending into the mineralised stratum Il.

When the borehole I5 reaches the mineralised stratum Il, the sinking unit I8 is removed and an excavating unit generally indicated by the reference numeral 3 is substituted therefor. The excavating unit is of similar construction to the sinking unit and comprises a main pipe 4l, an upcast pipe (i2, a branch pipe @.3 by which water under pressure is supplied to the main pipe, an end closure plate 4d! and a nozzle 125. The nozzle is directed in a horizontal direction so that the jet of water which issues therefrom has either a tangential component of movement as shown in Figures G and 8 or a radial movement only as shown in Figure 10. In use, Water is supplied to the main pipe by the pump unit 35 and issues from the nozzle 45 as a high pressure Waterjet which is directed on to the mineralised stratum surrounding the lower end of the excavating unit. The excavating unit is oscillated either through a complete circle as shown in Figures 8 and 10 or through an arc of a circle as shown in Figure 6 so as to Wash away the material to beexcavated over a complete circle surroundingr the 'lower end of the. excavating unit or over a sector having as its centre the lower end of the excavating unit. The material so washed away is carried up through the upcast pipe i2 to above the surface of the workings and then passes along the pipe 38 as described above.

When the excavation takes place on the boundary of a property, it is preferred that the material be removed by oscillating the excavating unit only through an angle of about 180 as shown in Figure 6 so that material is removed from the mineralised stratum to that side of the axis of the excavating unit which lies within the property of the person performing the excavation.

As shown in Figure 7, compressed air is introduced, if desired, below the apron 23 and around the excavating unit d. The compressed air for this purpose may be supplied by a pipe le which connects with a reservoir 41 (Figure 1). The compressed air so supplied will displace the water in the ground around the lower end of the excavating unit so that an air space 55 is formed in the excavated cavity. The pressure of the compressed air is selected so as to displace the water in the excavated cavity so that the nozzle is uncovered and so that the lower end of the upcast pipe remains submerged. With this arrangement the jet of Water is enabled to Work in the air space 55 and therefore is more effective so that the excavation can proceed more rapidly'.

In the arrangement shown in Figure 9 the excavating unit 49 is provided with a pump to draw the water and disintegrated mineral material which is suspended therein from the excavated cavity and to deliver it up the upcast pipe. The pump may be a submersible gravel pump or a self-priming pump located above the lower end of the excavating unit or any other pump which will work in a confined space, preferably however the pump is of the form shown in Figure 9 or 11. In Figure 9 the lower end of the upcast pipe 42 is provided with a Venturi constriction 5S and there is provided an injector nozzle 49 concentric therewith through which water is forced thus tending to draw up Water from the excavation and to deliver it into the upcast pipe through the constriction under increased pressure. The water is forced through the nozzle 49 by a pump 5i?, the suction side of which is submerged in a pool of water 5I in the excavation cavity. In the arrangement shown in Figure 11 the upcast pipe is provided with a Venturi constriction 48 the lower end of which is provided with a plurality of nozzles 52 through which a part of the high pressure water in the main pipe 4I may pass thus tending to draw up liquid from the lower end of the upcast pipe. The use of a pump as described assists in keeping the cavity which is being excavated free of water and in some cases the suction may be sufficient to ensure that the cavity (as shown in Figure 9) can be formed with an air space 55 without the use of compressed air as described with reference to Figure 7.

Although the sinking unit was stated above to be replaced by an excavating unit when the borehole I5 was formed, this is not necessary when a combined sinking and excavating unit is provided. Thus, two sets of nozzles may be provided,

Y 5 one set 53 being horizontally directed and the other set 54 being directed downwardly to perform the boring operation (see Figure 11).

If mining operations on a substantial scale are contemplated a number of units, such as the above, will be employed and while one is being sunk through a bore-hole others may be employed in excavating the desired material from beneath the overburden. VThe units may be suspended from gantries, cranes or the like or they may be mounted on movable objects such as pontoons or caterpillar track vehicles or the like.

The application of this invention is particularly suitable where overburden covers comparatively different layers of mineralised ground of a kind which lends itself to be disintegrated by jets or swirling water. Although mining and prospecting would be the main application of the invention it can also be used for excavating foundations and the like.

It will be understood that the pipes of the unitsv can be built up in sections which are screwed together as the unit is lowered into the bore-hole and that vthe sections may be stepped if desired so that the bottom section is the smallest.

It is also possible, if desired, to rell the worked out cavities in the ground by passing down into them material which is suspended in water and which, being directed into the cavity, is allowed to settle and the water thereafter withdrawn without carrying with it the solid material.

We claim: An apparatus for excavating subterranean deposits which comprises a double conduit adapted to be forced into the ground, means for forcing pressure uid downwardly through one portion of said conduit, jet orifices extending downwardly and laterally from said pressure fluid conduit, and jet orifices extending inwardly and upwardly from said pressure iiuid portion of the conduit into the other portion thereof, and means REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 823,749 Wanner June 19, 1906 1,607,586 Claytor Nov. 16, 1926 1,960,932 Tracy May 29, 1934 2,204,018 Kingsley June 11, 1940 2,251,916 Cross Aug. 12, 1941 2,371,174 Kalix Mar. 13, 1945 FOREIGN PATENTS Number Country Date 89,840 Austria Oct. 25, 1922 

